Manufacture of mild-steel plates, sections, and the like



l Patented June 26,1928.

UNITED STATES PATENT: orricnr rumors enmsnaw mam, or HIGHER nnnmeromnnemn.

murac'ruzen or mnn-s'rnnnrm'rns, snc'rrons, um um. LIKE;

ramming, lpplieatlon nled February 17,1026, Serial m. 9,880, aim in arm-puma: mm, as, lest.

Thisinvention has reference to the manufacture orproduction of mild steel plates,

sections, orthe like, in which the unequal" elastic limit of the plate, section, or material, in both the longitudinal and lateral or difierent directions, produced by the usual,

rollingor forging is removed, and also the deformed structure of the said steel is restored. v

In a prior patent application Serial No.

630,389, of which thepresent applicant, F. G. Martin, is the applicant, a process'is de scribed of producing mild steel plates or material for usein ship building, in which 16 these' effects or results are accomplished; and it is found that,-by the adoption of that process ortreatment, not only are the said; efi'ects'produced in the plates or material,-

but also their elastic limit test is much high- I '20 er than in ordinary mild steel plateror' material, in the ratio of Lat least about 5 to" 8. Thatis; the elastic; limit of the or'ginal mild steel'has been'raised bythe process or treatment in the ratio of at least 8 to 15, with the result that ships of mild steel can be built of very substantially: less weight,

than'heretofore, as therein stated.

The present application for patent is for the manufacture and use of mild steel plates, sections, or the like, for structures otherthan Shl s-such as bridges, and pther plate and gir er work, buildings, veh1cles,. boilers, rolling stock, and the like, in which the .work is subjected to more "or le'ssvsevere 85 stresses-produced b the process ortreat ment, consisting of heating-them throughout to 800 to 900 (1., and subsequently rapidly cooling them by causing currents of air to pass -'over their surfaces, or where *0 suitable or convenient by immersing them in or subjecting themto water or oil. This heat treatment or recess produces plates or material having t e characteristics stated, and enables relatively thin plates or 6 material to be safely used in structures such as referred to,'which -are subjected largetheir transverse elastic characteristics; and

this may be 'efiected by testing edge trim min s cut from the side-edges-or margins of the cat treated plates, material, or members, and those taken from'their end edges whether the elastic qualities required in the I plate in the difl'erent directions,-are equal,

and of the standard require To enable these testin s to be quickly performed, test pieces 0 T-headed form may-be cut out e f-"the said longitudinal-and or margins, so that it will be ascertained lateral trimmings or margins in. any; suit- I able. way, and their heads are, placed in a testing machine having, grippers of a kind which enable them to =be quickly put in,

gripped, tested; andtaken out.'

Such a. mechanism is illustrated-in the"- jspecifica-tionof the said former application for patent, Serial No. 630,389, and described therein.

By this means-rapid "and accurate testing of a large proportion of, or every plate and section or mem'ber'of mild steel used can be effected, andthe elastic limit of every tested plate, 860M011 or member used known, so

that it is not necessary to assume large facthr's of safety in plates, sections, or mate-- rial used in bridge work, girder work, hoih ers, and other structures, subject to stress,

as 'has been hitherto deemed to be neces sary; and by this invention relatively thin platescan be safely used resulting in a rel-- atively light structure.

What is claimed is so I K process for treating mlld -steel plates f"- which through their rolling or forging treatment have produced a steel'with' a material .-inequality of longitudinal and lateral I elastic limits, consisting in heating. the

plates to between 800;and 900 centigrade and then rapidlv cooling the plates artifi cially'to thereby equalize the elastic limit in all directions,v andymaterially increase such elastic limit over that of the plates as rolled or forged without in any particular increasing the hardness of the steel as a. l'Q v I sult-of the. process.

In' testimony'whereof I have signed name to this specification.

r; e JMARTIRL 

